Coalesced QoS: A pragmatic approach to a unified model for KLOS

Abstract

Advances in software and hardware technologies have given operating systems the ability to process data and handle various concurrent processes. The increased ability has been one of the driving forces which have led to the proliferation of mechanisms in operating systems to satisfy the performance requirements of applications with predictable resource allocation. As different classes of applications require different resource management policies one needs to look into ways to satisfy all classes of applications. Conventional general purpose operating systems have been developed for a single class of best-effort applications, hence, are inadequate to support multiple classes of applications. We present an abstract architecture for the support of Quality of Service (QoS) in Kernel-Less Operating System (KLOS). We propose new semantics for the QoS resource management paradigm, based on the notion of Quality of Service. By virtue of this new semantics, it is possible to provide the support required by KLOS to various components of the operating system such as memory manager, processor time, IO management etc. These mechanisms which are required within an operating system to support this paradigm are described, and the design and implementation of a prototypical kernel which implements them is presented. Various notions of negotiation rules between the application and the operating systems are discussed along-with a feature which allows the user to express its requirements and the fact is that this model assures the user in providing the selected parameters and returns feedback about the way it meets those requirements. This QoS model presents a design paradigm that allows the internal components to be rearranged dynamically, adapting the architecture to the high performance of KLOS. The benefits of our framework are demonstrated by building a simulation model to represent how the various modules of an operating system and the interface between the processes and the operating system can be tailored to provide Quality of Service guarantees. © 2006 Springer.